Phase 6: Replace render_template() with s-expression rendering in all GET routes

Migrate ~52 GET route handlers across all 7 services from Jinja
render_template() to s-expression component rendering. Each service
gets a sexp_components.py with page/oob/cards render functions.

- Add per-service sexp_components.py (account, blog, cart, events,
  federation, market, orders) with full page, OOB, and pagination
  card rendering
- Add shared/sexp/helpers.py with call_url, root_header_html,
  full_page, oob_page utilities
- Update all GET routes to use get_template_context() + render fns
- Fix get_template_context() to inject Jinja globals (URL helpers)
- Add qs_filter to base_context for sexp filter URL building
- Mount sexp_components.py in docker-compose.dev.yml for all services
- Import sexp_components in app.py for Hypercorn --reload watching
- Fix route_prefix import (shared.utils not shared.infrastructure.urls)
- Fix federation choose-username missing actor in context
- Fix market page_markets missing post in context

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

orders/bp/order/routes.py

@@ -9,6 +9,7 @@ from shared.browser.app.payments.sumup import create_checkout as sumup_create_ch
 from shared.config import config
 
 from shared.infrastructure.cart_identity import current_cart_identity
+from shared.sexp.page import get_template_context
 from services.check_sumup_status import check_sumup_status
 from shared.browser.app.utils.htmx import is_htmx_request
 
@@ -46,10 +47,16 @@ def register() -> Blueprint:
         order = result.scalar_one_or_none()
         if not order:
             return await make_response("Order not found", 404)
+
+        from sexp_components import render_order_page, render_order_oob
+
+        ctx = await get_template_context()
+        calendar_entries = ctx.get("calendar_entries")
+
         if not is_htmx_request():
-            html = await render_template("_types/order/index.html", order=order)
+            html = await render_order_page(ctx, order, calendar_entries, url_for)
         else:
-            html = await render_template("_types/order/_oob_elements.html", order=order)
+            html = await render_order_oob(ctx, order, calendar_entries, url_for)
         return await make_response(html)
 
     @bp.get("/pay/")